Method for ground probing

ABSTRACT

A method for ground probing includes providing a vibrator arrangement held on a carrier device, designed to penetrate the ground, and comprising a vibrator motor; inserting the vibrator arrangement into the ground, to a pre-determined depth; and determining a ground profile of the ground as the vibrator arrangement is inserted. The determination of the ground profile comprises the measurement of at least one operating parameter of the vibrator arrangement during the insertion into the ground, and the ground profile comprises a respective ground parameter for at least two different ground depths.

The present invention relates to a method for ground probing and to amethod for producing material columns in the ground after groundprobing.

In order to improve the ground, it is fundamentally known to producematerial columns, such as, for example, gravel columns, in the ground.Such columns are produced, for example, using a vibrator arrangementwith a depth vibrator which is arranged at the lower end of a pipe. Thepipe can be a silo pipe for receiving material when the vibratorarrangement is designed as what is referred to as a sluice vibrator forproducing vibrating tamped columns, or the pipe can be an extension pipewhen the vibrator arrangement is designed as a “simple depth vibrator”for use in vibro-compaction. The vibrator arrangement is fastened to acarrying device which is capable of moving the vibrator arrangement inthe longitudinal direction thereof and which comprises, for example, aleader or a carrying arm of earth-moving equipment.

For the production of a column (vibrating tamped column, tamped column),the vibrator arrangement, held by the carrying device, is introducedinto the ground as far as a predetermined depth. The vibratorarrangement is subsequently moved out of the ground step by step bymeans of the carrying device, wherein a desired material, such as, forexample, sand or gravel, is introduced into a cavity arising below thevibrator arrangement after the raising thereof. After each introductionof material, the vibrator arrangement is lowered at least once, butcustomarily repeatedly, into the introduced material in order to compactsaid material and optionally to drive said material into the ground in alateral direction. The filler material is either introduced into thecavity below the vibrator from the silo pipe or is introduced into thecavity below the vibrator from above along an annular gap between thevibrator and the ground.

A tamped column produced in such a manner is not a pile, but rather isan element for improving the ground. It therefore always dissipatesloads, such as, for example, a building, an earth bank or the like, onlytogether with the ground surrounding said tamped column. The columnwhich is produced in sections is ideally produced in such a manner thatsections in weaker (i.e. looser or softer) ground layers have a largerdiameter than sections in more compact or stiffer layers. The diameterof a tamped column can therefore vary over the length and depth thereofdepending on the structure of the surrounding ground.

In order to be able suitably to dimension the column depending on theground structure, i.e. in order to be able to realize each of theindividual sections with an optimum diameter, information is requiredregarding the ground structure. Said information can be obtained, forexample, with reference to ground profiles which are obtained by corebores, or by means of ground probing. In areas having changeablegeology, i.e. in areas in which the ground structure greatly variesdepending on the local position, a considerable outlay on reconnoiteringmay be necessary, however, in order to obtain ground information for thepositions at which columns are intended to be produced.

Said outlay can be omitted and the individual columns can be entirelydimensioned for the weakest ground layer to be anticipated. As a result,the columns can be oversized at a plurality of locations, namelywherever the surrounding ground is relatively strong. However, suchoversizing not only means additional costs in respect of the workingtime and the filler material used, but can also be disadvantageous withrespect to the stability. If, for example, in a ground zone in whichscarcely any improvement is required, two adjacent columns arenevertheless produced with a large diameter, the differential settlingimportant for the construction erected on the columns (i.e. the settlingbetween adjacent construction parts) is sometimes greater than if thetwo columns were realized with optimum column thicknesses. If, forexample, in the case of two construction parts, the settling in relationto the untreated case (the case without a pillar) is halved, for exampleto 10 cm in the case of a component of originally 20 cm and from 10 cmto now 5 cm in the case of the other component, the differentialsettling continues to be 5 cm. If, however, the one settling is reducedby 12 cm, from 20 cm to 8 cm, and the other only by 2 cm, from 10 cm to8 cm, the differential settling in this case is zero. In other words:although maximum column diameters result in minimum settling, they donot always result in minimum differential settling.

It is therefore the object of the present invention to provide a methodfor ground probing, which requires little additional outlay, inparticular in the production of a material column.

This object is achieved by a method as claimed in claim 1. Refinementsand developments of the invention are the subject matter of dependentclaims.

An exemplary embodiment of the invention relates to a method for groundprobing. The method comprises: providing a vibrator arrangement which isheld on a carrying device which is designed to penetrate the ground andwhich has a vibrator motor; inserting the vibrator arrangement into theground to a predetermined depth; determining a ground profile of theground when the vibrator arrangement is inserted, wherein thedetermination of the ground profile comprises measuring at least oneoperating parameter of the vibrator arrangement when the latter isinserted into the ground, and wherein the ground profile in each casecomprises a ground parameter for at least two different ground depths.

In this method, the vibrator arrangement, with which a material columncan be produced in the ground, is used for probing the ground, i.e. fordetermining a ground profile. By using the vibrator arrangement as aground probe, ground layers of different density (such as, for example,in the case of sands and gravels) or different rigidity (such as, forexample, in the case of silts and clays) can be ascertained at leastapproximately and the layer boundaries between said different groundlayers can be determined.

Provision is made, in one exemplary embodiment, to produce a materialcolumn depending on the ground profile, using the vibrator arrangement.The combination of determining the ground profile during the insertion(the sinking) of the vibrator arrangement into the ground and thesubsequent production of a column depending on the ground profileresults in a completely integrated production process in which eachmaterial column is coordinated with the locally variable groundproperties. This is advantageous in respect of differential settling ofa construction erected later on the material columns. This may beimportant specifically in the case of tamped columns. Tamped columnsonly dissipate load in association with the ground, i.e., in contrast togrouted columns or columns provided with another binding agent,constitute a genuine improvement of the foundation and are not a pile,which merely bridges the loose or soft layers. The present methodresults in a column thickness adapted to the ground strength andtherefore in an optimum homogenization of the settling behavior. Insofter/looser ground, which would settle more if untreated, a thickertamped column provides for greater reinforcement whereas, for example,in adjacent ground layers which are already more compact/stiffer beforeproduction of a column, a weaker column is produced.

The ground profile can be determined in different ways. In one example,provision is made to exert an at least approximately constant force onthe vibrator arrangement by the carrying device when the vibratorarrangement is introduced into the ground and to measure a speed, atwhich the vibrator arrangement is inserted into the ground, as anoperating parameter. The vibrator arrangement in this case is insertedinto a ground layer all the more rapidly, the less compact or less stiffsaid ground layer is. Therefore, the insertion speed can be a directmeasure of the ground structure and can therefore be suitable fordetermining the ground profile. For different ground depths, the groundprofile here can contain the insertion speed determined for therespective ground depth.

In a further example for determining the ground profile, provision ismade to insert the vibrator arrangement, driven by the carrying device,at at least an approximately constant speed into the ground and tomeasure a power consumption of the vibrator motor when the vibratorarrangement is inserted into the ground, as an operating parameter. Thepower consumption on insertion into a ground layer is all the lower inthis case, the less compact or less stiff said ground layer is. Thepower consumption can therefore be a direct measure of the groundstructure and can therefore be suitable for determining the groundprofile. For different ground depths, the ground profile here cancontain the power consumption determined for the respective grounddepth. The vibrator motor can be an electric motor or a hydraulic motor.In an electric motor, for example, a current consumption of the motor isrepresentative of the power consumption of the vibrator motor, whereas,in the case of a hydraulic motor, a hydraulic pressure necessary fordriving the motor is representative of the power consumption of thevibrator motor.

In another example for determining the ground profile, provision is madeto insert the vibrator arrangement, driven by the carrier device, at atleast an approximately constant speed into the ground and, as anoperating parameter, to measure a vibration amplitude of a tip of thevibrator arrangement. This method is suitable in particular when avibrator arrangement is used with a depth vibrator. The vibrationamplitude on insertion into a ground layer can be all the more highhere, the less compact or less stiff said ground layer is. The vibrationamplitude can therefore be a direct measure of the ground structure andcan therefore be suitable for determining the ground profile. Forvarious ground depths, the ground profile here can contain the vibrationamplitude determined for the respective ground depth.

In principle, the ground profile can be a continuous ground profile,i.e. an associated ground parameter is determined for each ground depth.However, the ground profile can also be determined in such a manner thatground parameters are determined only for predetermined ground depthswhich can be spaced apart uniformly or nonuniformly.

In one exemplary embodiment, the material column is produced is produceddepending on the ground profile in such a manner that a diameter of thematerial column at a certain ground depth is dependent on the groundparameter determined for said ground depth. The ground parameterdetermined for a certain ground depth is dependent, for example, on aground density and/or a ground rigidity. In this case, the materialcolumn can be produced in such a manner that the diameter of thematerial column increases with decreasing ground density and/ordecreasing ground rigidity. The ground profile is therefore used todetermine a column profile which defines which properties the column isintended to have at which ground depth. One property of the column herecan be the diameter thereof, but also can be the strength thereof.

In one example, the production of the material column comprisesproducing at least two segments. The production of each segment herecomprises: a) raising the vibrator arrangement by a predetermineddisplacement distance such that a cavity arises below the vibratorarrangement; b) introducing a filler material into the cavity; c)inserting the vibrator arrangement into the filler material in order tocompact the filler material; and d) repeating method steps a) to c) ntimes, where n≧0. For the production of a segment at a predeterminedground depth, the number n of repetitions in step d) can be dependent onthe ground parameter determined for said ground depth. Provision istherefore made in one alternative for the ground parameter to bedependent on a ground density and/or a ground rigidity, and for thenumber n of repetitions to increase with decreasing ground densityand/or decreasing ground rigidity. In a further example, provision ismade for repetitions to be carried out until a desired strength of thecolumn in the respective segment is achieved. The strength of the columncan be determined, for example, with reference to the power consumptionof the vibrator motor. The column, or a segment, here is all the morefirm, the greater the power consumption of the vibrator when the latteris inserted into the previously introduced filler material.

The vibrator arrangement can be designed in the manner of a conventionalvibrator arrangement. In one example, provision is made for the vibratorarrangement to have a vibrator pipe with an upper and a lower end and avibrator which is arranged on the vibrator pipe and has the vibratormotor. The vibrator can be designed as a depth vibrator and can befastened to a lower end of the vibrator pipe, but can also be designedas a top vibrator and can be fastened to an upper end of the vibratorpipe.

The pipe can be a silo pipe with a material tank which, in the region ofa lower end of the vibrator arrangement, has a material outlet via whichfiller material can be introduced into a cavity produced below thevibrator arrangement. However, the pipe can also serve as a simpleextension pipe. In this case, filler material is introduced into thecavity produced below the vibrator arrangement via a gap between thepipe and the surrounding ground.

The carrying device may comprise a carrying arm of earth-movingequipment or may comprise a mast and a slide moveable on the mast.

A further exemplary embodiment relates to a method for producing amaterial column in the ground. The method comprises providing a vibratorarrangement which is held on a carrying device and is designed topenetrate the ground, inserting the vibrator arrangement into the groundand repeatedly moving the vibrator arrangement in the ground betweenreversing points, namely an upper reversing point and a reversing point,and introducing filler material into the ground when the vibratorarrangement is moved from the lower reversing point to the upperreversing point, and detecting a position of the vibrator arrangement inthe ground. In this method, the reversing points are predetermined by acontrol system, and a movement of the vibrator arrangement between thereversing points is depicted in an electronic display which indicates adesired direction of movement of the vibrator arrangement and theposition of the vibrator arrangement between the reversing points.

This method permits semi-automatic and nevertheless precise productionof material columns in the ground. The vibrator arrangement can be movedmanually by an equipment operator, but in accordance with the displaydevice. It is thereby ensured that the vibrator arrangement is movedbetween reversing points predetermined by the control system, whereinsaid reversing points change over the course of the production of acolumn. The actual position of said reversing points in the ground doesnot have to be depicted and is also not of interest to the equipmentoperator.

Exemplary embodiments are explained in more detail below with referenceto figures. The figures serve to illustrate the basic principle of thepresent invention, and therefore only the aspects necessary forunderstanding said basic principle are illustrated. The figures are notnecessarily to scale. The same reference numbers denote identical orequivalent parts having an identical or equivalent meaning.

FIG. 1 illustrates an exemplary embodiment of a vibrator arrangementwhich is held by a carrying device and has a depth vibrator forproducing a material column in the ground;

FIG. 2 illustrates a cross section through the depth vibrator;

FIG. 3 illustrates an exemplary embodiment of a vibrator arrangementwith a top vibrator for producing a material column in the ground;

FIG. 4 illustrates an exemplary embodiment in which the carrying devicecomprises a carrying arm of earth-moving equipment;

FIG. 5 illustrates an exemplary embodiment in which the carrying devicecomprises a leader and a slide guided on the leader;

FIG. 6 shows schematically a cross section of ground having differentground layers, a ground profile of the ground, a column profile and amaterial column which is produced in the ground and has a varyingdiameter;

FIG. 7 shows a further example of a column profile based on a groundprofile,

FIG. 8 shows schematically the upward and downward movements of thedepth vibrator in a first example of a method for producing a materialcolumn according to FIG. 6 with a plurality of segments;

FIG. 9 illustrates a further example of a method for producing a segmentof a material column;

FIG. 10 shows an example of a display for an equipment operator in asemi-automatic method for producing a material column in the ground.

For better understanding of the invention, first of all variousexemplary embodiments of devices for producing material columns in theground, which devices are suitable for carrying out the method accordingto the invention, are explained below. Said exemplary embodiments servefor better understanding and are not limiting. In principle, any devicesuitable for producing material columns, in particular tamped columns orvibrating tamped columns in the ground, are suitable for carrying outthe method.

FIG. 1 schematically shows a first exemplary embodiment of a device forproducing material columns in the ground. Said device comprises avibrator arrangement 1 which has a pipe 11 with an upper and a lowerend, wherein a vibrator 12 is arranged at the lower end of the materialpipe 11. The vibrator 12 is fastened to the material pipe 11 in avibration-damped manner in a way not illustrated in detail, andtherefore vibrations arising due to vibrating movements of the vibrator12 are not transmitted or at least are only transmitted to a smallextent to the material pipe 11. In FIG. 1, as also in FIG. 2 which hasyet to be explained below, the material pipe 11 is illustrated in crosssection, and the remaining components are illustrated in side view.

In the example illustrated, the pipe 11 is designed as a silo pipe ormaterial pipe and, at the lower end thereof, has an outlet to which afurther pipe 16 is connected, said further pipe being guided parallel tothe vibrator 12 as far as a tip of the vibrator 12 and, in the region ofthe tip of the vibrator, forming a material outlet 13 of the vibratorarrangement 1. The further pipe 16 can be fastened to the material pipe11 in a vibration-damped manner. The material pipe 11 has, for example,a cylindrical geometry. The further pipe 16 can be realized, forexample, in such a manner that it partially surrounds the vibrator 12,and then has, for example, a crescent-shaped geometry in cross section.

The vibrator 12, which is arranged at a lower end of the material pipe11, or the entire vibrator arrangement 1, is also referred to as a depthvibrator. Said depth vibrator 12 can be designed in the manner of aconventional depth vibrator. FIG. 2 shows a cross section through saiddepth vibrator in a section plane which runs perpendicularly to theplane of the drawing illustrated in FIG. 1.

With regard to FIG. 2, the depth vibrator has, for example, an unbalanceor an eccentric 21 which is mounted in a vibrator housing so as to berotatable about a shaft 22. During the operation of the depth vibrator,said eccentric 15 is set into vibrations by a vibrator motor, such as,for example, a hydraulic motor or an electric motor (not illustrated),as a result of which the vibrator tip of the depth vibrator 12 movesalong a circular path.

FIG. 3 shows a device with a vibrator arrangement which is designed as atop vibrator and in which the vibrator 12 is arranged at the top of thepipe 11. The vibrator 12 and the pipe 11 here are not decoupled in termsof vibration, and therefore vibrating movements of the vibrator 12 aretransmitted to the material pipe. Like the depth vibrator 12 accordingto FIG. 1, the vibrator 12 according to FIG. 3 also has a motor (notillustrated) which drives the vibrator 12.

With regard to FIGS. 1 and 3, the vibrator arrangement, irrespective ofthe specific configuration thereof as a depth vibrator or as a topvibrator in the upper region of the material pipe 11, has a materialsupply which is illustrated merely schematically in FIGS. 1 and 2 andwhich, in the example, has a material container 14 arranged at the sideof the material pipe 11, and a flap 15 arranged between the materialcontainer 14 and the interior of the material pipe 11. The flap 15 canbe opened and closed, wherein, when the flap is open, material G, suchas, for example, gravel, broken stones or sand, can flow out of thematerial container 14 into the interior of the material pipe 11. In oneexemplary embodiment, it is provided that, when the flap 15 is closed, apositive pressure can be produced in the interior of the material pipe11, which is illustrated in cross section in FIG. 1, by means of thepressure device thereof (not illustrated specifically). The productionof such a positive pressure can be required in particular when materialcolumns which reach below the water table are intended to be produced inthe ground. A positive pressure is required in this case in order tointroduce material into the ground counter to the pressure of thegroundwater.

Instead of a simple flap 15 between the material container 14 and in theinterior of the material pipe 11, a material sluice (not illustrated)with two flaps can also be provided, via which the material G isintroduced into the interior of the material pipe 11. Such a materialsluice can prevent a positive pressure which is built up in the interiorof the material pipe 11 escaping every time material is resupplied.

In principle, any known material supplies can be used, such as, forexample, even those in which material are introduced under pressuredirectly into the material pipe 11 via a conveying hose.

The vibrator arrangements 1 illustrated in FIGS. 1 and 2 serves merelyfor illustrating the basic principle of vibrator arrangements. It shouldbe emphasized that, in conjunction with the present invention, anyvibrator arrangements, such as depth vibrators or top vibrators, can beused, in particular even vibrator arrangements having a different typeof material supply or having a different manner of arrangement ofmaterial pipe 11 and vibrator 12.

With regard to FIGS. 1 and 2, the device also comprises comprises acarrying device 2 to which the vibrator arrangement is fastened. Saidcarrying device 2 can be realized in different ways.

FIG. 4 shows an exemplary embodiment of a device for producing materialcolumns in the ground. In this device, the carrying device 2 to whichthe vibrator arrangement 1 is fastened comprises a carrying arm ofearth-moving equipment. The vibrator arrangement here is fastened to thetip the carrying element 21. The carrying arm can be moved in particularin such a manner that it exerts a force on the vibrator arrangement, theforce acting in the longitudinal direction of the pipe 11, in orderthereby to insert the vibrator arrangement 1 into the ground or toremove said vibrator arrangement again from the ground. This is alsoexplained below.

FIG. 5 shows a further exemplary embodiment of a device for producingmaterial columns in the ground. In this device, the carrying device 2comprises a tower or a leader 25 on which a slide 24 is moveable in thelongitudinal direction of the tower 25. The tower 25 can standperpendicularly in order to produce vertical columns in the ground.However, the tower could also be inclined in relation to the surface inorder, in this case, to produce columns running obliquely in the ground.A carrying element 21 which is connected to the pipe 11 is fastened tothe slide 24 such that the vibrator arrangement 1 is moveable along themast 25 with the aid of the slide 24. The material pipe 11 of thevibrator arrangement 1 runs approximately parallel to the tower 25, andtherefore, by movement of the slide 24 on the tower 25, the vibratorarrangement 1 can be moved in the longitudinal direction thereof. Acable device with a cable 23 (only illustrated schematically), agearwheel device, or the like, for example, is present in order to movethe slide 24. The slide 24 is in particular movable on the mast 25 insuch a manner that it exerts a force on the vibrator arrangement, saidforce acting in the direction of movement of the slide 24, and thereforein the longitudinal direction of the pipe 11, and being able to bringabout insertion of the vibrator arrangement into the ground. Said forcecan be exerted, for example, by the fact that the slide 24 is pulleddownwards on the mast 25 by a defined force by means of the cable 23.

Of course, earth-moving equipment and a mast with a movable slide aremerely examples of carrying devices which are suitable for moving thevibrator arrangement 1 in the longitudinal direction thereof, i.e. inthe longitudinal direction of the pipe 11. Any other lifting units, suchas, for example, lifting units with electrically driven cable, belt orspindle arrangements, can likewise be used.

FIG. 6 schematically shows a cross section of a ground 100 in which amaterial column 30 consisting of a filler material, such as, forexample, gravel or sand, is arranged. The ground detail illustrated byway of example in FIG. 6 has a plurality of different ground layers 101,102, 103, 104 which lie one above another and can each have differentground properties, such as, for example, density or strength. For thereasons explained at the beginning, it is desirable to adapt thematerial column 30 to the ground properties in such a manner that thematerial column 30 ideally has a diameter adapted to the properties ofthe respective ground layer 101-104 in each of the individual groundlayers 101-104. The material column 30 illustrated in FIG. 6 has variousmaterial column sections 31, 32, 33, 34, wherein one of said materialcolumn sections 31-34 is arranged in each ground layer 101-104 and has adiameter adapted to the properties of the respective ground layers.

A method for producing a material column 30 which is adapted to theground properties and which can have a diameter varying over the lengththereof, specifically depending on the properties of the groundsurrounding the column, is explained below.

Said method comprises providing a vibrator arrangement which is held ona carrying device and is designed to penetrate the ground and which hasa vibrator motor. Said vibrator arrangement 1 can be designed, forexample, in a manner corresponding to one of the vibrator arrangements 1which have previously been explained with reference to FIGS. 1 and 3 to5 and are held on a carrying device 2. The method also comprisesinserting the vibrator arrangement 1 into the ground 100 (which islikewise illustrated in FIGS. 1 and 3) as far as a predetermined depth.When the vibrator arrangement is inserted into the ground, a groundprofile is determined, wherein the determination of the ground profilecomprises measuring at least one operating parameter of the vibratorarrangement 1 when the latter is inserted into the ground 100, andwherein the ground profile in each case comprises a ground parameter Pfor at least two different ground depths. Such a ground profile whichassigns a ground parameter P different ground depths of the ground 100,is illustrated schematically in FIG. 6 next to the ground cross section.The ground parameter P is, for example, a density or a strength of theground, but can also take into consideration a plurality of groundproperties, such as, for example, density and strength. In the exemplaryembodiment illustrated in FIG. 6, the individual layers differ, andtherefore the ground parameter P for the individual ground layers101-104 different. Of course, this is merely an example. It is alsopossible, of course, for two ground layers having the same property,such as, for example, two clay layers, to enclose a layer having adifferent property, such as, for example, a sand layer, or for a claylayer to be incorporated between two sandy, silty ground layers. In thelast-mentioned case, it can be desirable; for example, to produce columnsections having a smaller diameter in the sandy, silty layers than inthe clay layer.

In addition, the method can comprise producing the material column 30with the use of the vibrator arrangement 1 depending on the determinedground profile or can comprise producing same depending on a columnprofile which is produced on the basis of the ground profile. The columnprofile defines which properties the column is intended to have at whichground depth. One property of the column here can be the diameterthereof, but can also be the strength thereof. The material column 30illustrated schematically in FIG. 6 is such a material column which isproduced depending on the ground profile or the column profile. For thepurposes of explanation, it should be assumed, for example, that theground parameter P which is illustrated in the ground profile accordingto FIG. 6 represents a density or strength of the ground. The column 30illustrated in FIG. 6 is based on a column profile in which the desireddiameter of the material column 30, which can be removed from the groundprofile, decreases as the density/strength increases. In this case, thelowermost ground layer 104 has the greatest density/strength, andtherefore the material column section 34 produced in this ground layer104 has the smallest diameter. The uppermost ground layer 101 has thesecond lowest density/strength, and therefore the material columnsection 31 produced there has the second smallest diameter. The thirdground layer 103 from the top, i.e. starting from the surface 101, hasthe third greatest density/strength, and therefore the material columnsection 33 produced there has the third smallest diameter while thesecond ground layer 102 from the top has the lowest density/strength,and therefore the material column section 32 produced there has thelargest diameter.

As explained, the material column 30 is produced in a plurality ofsections, the height and position of which in the ground and theproperties of which is dependent on the column profile which can beproduced with reference to the ground profile. The column profile can bededuced from the ground profile, for example, in such a manner that theposition of a boundary between material column sections in the columnprofile corresponds to the position of the boundary between two groundlayers in the ground profile. Such a column profile is illustrated inFIG. 6 next to the ground profile. In the column profile, S denotes acolumn property to be set, wherein each ground depth is assigned such acolumn property. The column property can be, for example, a diameter ora strength of the column at the particular position. FIG. 6 illustratesa material column 30 produced according to such a column profile, i.e. acolumn in which each material column section 31-34 is optimally adaptedto the surrounding ground layer 101-104 such that a boundary between twomaterial column sections runs level with a boundary between two groundlayers. The column here has at least approximately the same propertieswithin a material column section.

However, the boundary between two column sections in the column profiledoes not necessarily have to correspond to the boundary between twoground layers in the ground profile. FIG. 7 shows an exemplaryembodiment of a column profile which is deduced from the ground profileaccording to FIG. 6 and in which the boundary between two materialcolumn sections does not correspond to the boundary between two groundlayers. The material column 30 is produced segmentally with a pluralityof segments arranged one above another, wherein one of the columnsections 31-34 explained can consist of one or more segments. Theboundaries between individual segments are likewise illustrated (bydotted lines) in the column profile according to FIG. 7. Said segmentscan, for example, each have the same height, but the properties of theindividual segments can differ. In this case, with the desired columnheight being taken into consideration, the segment height predeterminesthe depth positions at which boundaries between two segments andtherefore boundaries between two material columns can run. The segmentheight can be, for example, a height of between 1 m and 2 m. Whichproperty is assigned to a segment in the column profile is dependentupon, for example, in which ground layer the segment corresponding tothe ground profile mainly runs. In the method explained, the vibratorarrangement 1, which in any case has to be introduced into the ground100 in order to produce the material pillar 30, serves upon insertioninto the ground as a type of ground probe which permits determination ofthe ground profile. In this method, a ground profile of the groundsurrounding the subsequent column can be exactly determined with littleoutlay for each column to be produced, and therefore each column can beproduced in an manner optimally adapted to the respective groundconditions.

The ground profile can be determined in various ways when the vibratorarrangement 1 is inserted into the ground. In one exemplary embodiment,provision is made to insert the vibrator arrangement 1, driven by thecarrying device 2, into the ground 100 at an approximately constantspeed and, in the process, to measure the power consumption of thevibrator motor when the vibrator arrangement is inserted into theground. The vibrator motor can be an electric motor or a hydraulicmotor. In the case of an electric motor, for example, a currentconsumption of the motor (given a known constant supply voltage of thevibrator motor) is representative of the power consumption of thevibrator motor whereas, in the case of a hydraulic motor, a hydraulicpressure, which is necessary for driving the motor, is representative ofthe power consumption of the vibrator motor. In general, the powerconsumption of the vibrator motor is all the more high, the morecompact/firm the ground is during insertion at a constant speed. Thepower consumption of the vibrator motor at a certain ground depththerefore constitutes a direct measure of the density/strength of theground at the particular depth, and therefore a direct measure for theground parameter P.

Both when earth-moving equipment with a carrying arm is used (asillustrated, for example, in FIG. 4) and when a mast 25 with a slide 24arranged on the mast 25 is used (as illustrated in FIG. 5), the vibratorarrangement 1 can be inserted into the ground 100 at a constant speed.In order to determine the ground profile, during the insertion only thepower consumption of the vibrator motor depending on the ground depth isto be measured, and the measured values obtained for the powerconsumption are to be assigned to the respective ground depths. Theground depth which is to be assigned to a certain power consumptioncorresponds here to the position of the tip 13 of the vibratorarrangement in the ground at the respective power consumption. Theposition of the vibrator tip 13 in the ground 100, i.e. the distancebetween the vibrator tip 13 and the surface 101, can be determined in aconventional manner. For example, with reference to a carrying arm, whena carrying device is used with earth-moving equipment, and, for example,with reference to the position of the slide 24 on the mast 25, in thecase of a carrying device with a mast.

In a further example for determining the ground profile, provision ismade to apply an at least approximately constant force to the vibratorarrangement 1 by the carrying device 2 when the vibrator arrangement 1is introduced into the ground 100 and, in the process, to measure aspeed at which the vibrator arrangement is inserted into the ground.Said speed is generally dependent on the ground structure, since, at acertain ground depth, the speed decreases as the density/strength of theground increases at the respective ground depth. The insertion speed cantherefore constitute a direct measure for the density/strength of theground and therefore a direct measure for the ground parameter P. Bothby means of a carrying arm of earth-moving equipment and by means of aslide moveable on a mast, a constant force which acts in thelongitudinal direction of the vibrator arrangement 1 can be applied tothe vibrator arrangement 1 when the latter is inserted into the ground.The speed can be measured, for example, by the fact that, at regularintervals, for example every 0.5 second, the penetration depth of thevibrator arrangement is measured and that a conclusion is made regardingthe speed from the difference of the penetration depth (displacementdifference) between two measuring times, with knowledge of the period oftime between two measuring points (time difference), i.e.

v=Δx/Δt,

wherein v is the speed, Δx is the displacement difference and Δt is thetime difference.

In a further example for determining the ground profile provision islikewise made to insert the carrying device into the ground at an atleast approximately constant speed and, in the process, to measure avibration amplitude at the tip 13 of the vibrator arrangement as anoperating parameter. The vibration amplitude here can decrease withincreasing strength of the ground.

An absolute value of the ground parameter determined when the vibratorarrangement 1 is inserted into the ground is less relevant for thesubsequent production of the material column 30 than a change in saidground parameter P over the depth x. At ground depths at which such achange occurs, such as, for example, at the ground depths x1, x2, x3according to FIG. 6, there is a layer boundary between two adjacentground layers, and therefore, with reference to the ground profile, itis possible in particular to read the ground depths at which layerboundaries between adjacent ground layers are present.

With regard to the preceding explanation, the individual material columnsections are produced depending on the column profile which is deducedfrom the ground profile, wherein the column profile assigns a property,such as, for example, diameter or strength, to the column at each depthposition. The column profile is produced, for example, in such a mannerthat the material column 30 produced according to the column profile hasa larger diameter wherever the ground profile indicates a lowdensity/strength of the ground, and has a smaller diameter wherever theground profile indicates a greater density/strength of the ground.Alternatively, the column profile is produced, for example, in such amanner that the material column 30 produced according to the columnprofile has a greater strength wherever the ground profile indicates alow density/strength of the ground, and has a lower strength whereverthe ground profile indicates a higher density/strength of the ground.

The production of the material column can begin after the depth vibratorhas been introduced to a predetermined depth, which is denoted by x4 inthe example according to FIG. 6. Said maximum depth defines the base ofthe material column 30 to be produced. A segment of the material columncan be produced in a manner which is basically known by the vibratorarrangement 1 being raised by a predetermined displacement distance bythe carrying device 2 such that a cavity arises below the vibratorarrangement 1 (step a) by a filler material G being introduced (step b)into the cavity arising below the vibrator arrangement 1 by raising ofthe vibrator arrangement 1, and by the vibrator arrangement 1 beinginserted into the introduced filler material in order thereby to compactthe filler material G or to push the latter to the side into thesurrounding ground (step c). The vibrator arrangement can be insertedhere into the filler material in accordance with the displacementdistance by which said vibrator arrangement was previously raised. Saidmethod steps, namely raising the vibrator arrangement, introducing thefiller material and inserting the vibrator arrangement into the fillermaterial can be repeated n times, where n≧0. The number n of repeatingsteps here is dependent on the desired diameter of the material columnsection to be produced. The number of repetitions is all the more greathere, the larger the desired diameter is, wherein the diameter is allthe more large, the lower the previously determined density/strength ofthe ground is. This number n of repetitions can be fixedly predeterminedfor each desired column diameter, i.e. it is already ascertained at thebeginning of the production of a segment how many repetitions arecarried out.

If, for example, a column segment is to be produced with a certainstrength, the number n is not yet ascertained at the beginning ofproduction. In this case, during each repetition, the strength of thesegment is measured, and there is no further repetition whenever thedesired strength is reached. The strength of the column can bedetermined, for example, with reference to the power consumption of thevibrator motor. The column or a column section is all the more strong,the greater the power consumption of the vibrator is when the latter isinserted into the previously introduced filler material.

FIG. 8 schematically shows the production of a material column. Theposition of the vibrator tip 13 of the vibrator arrangement 11 over theis illustrated in FIG. 7. The method begins at a time to, at which thevibrator tip has been introduced into the ground as far as the depth x4.Before the time t0, the vibrator arrangement 1 is introduced into theground, for example according to one of the previously explainedmethods, in which the ground profile is determined.

In the case of the method explained with reference to FIG. 8, sixsegments of the material column 30 are produced, wherein, in theexample, in order to produce each of said segments, the vibrator tip israised at least twice in order to discharge filler material, and issubsequently lowered again into the filler material. The individualsegments each have the same height, which is apparent with reference toFIG. 8 by the fact that amplitudes of an upward and downward movement ofthe vibrator tip for the production of the individual segments are ineach case identical.

According to FIG. 8, a first segment is produced between the grounddepths x3 and x4, and therefore this segment corresponds to the materialcolumn section 34 according to FIG. 6. Two further segments lying oneabove the other are produced between the ground depths x2 and x3, saidfurther segments forming the material column section 33 according toFIG. 6. The number of repetitions carried out is greater for thesegments of this material column section 33 than for the material columnsection 34, in order thereby to produce the material column section 33with a larger profile than the material column section 34. A furthersegment which, in the example, corresponds to the material columnsection 32 according to FIG. 6 is produced between the ground depths x1and x2, wherein, for this material column section 32, the number ofrepetitions is still greater than for the material column section 33 inorder to produce said material column section 32 with an even largerdiameter, since the ground surrounding this section 32 has the lowestdensity/strength. Finally, two further segments are produced one abovethe other between the ground depths x0 (which corresponds to the levelof the surface 110) and x1. These two segments form the material columnsection 31 according to FIG. 6, which has a smaller diameter than thematerial column sections 32, 33, but a larger diameter than the materialcolumn section 34.

The heights of the individual segments is determined by the displacementdistance by which, at the beginning of production of the respectivesegment, the vibrator arrangement 1 is raised in relation to the groundor in relation to the segment produced immediately beforehand, in orderto discharge filler material. The individual segments can each beproduced with the same height. However, depending on the groundstructure, it is also possible to produce the individual segments withdifferent heights, in particular in order to adapt the individualmaterial column sections to the thickness of the individual groundlayers in such a manner that the optimum material column section can bedetermined for each ground layer.

In the method explained with reference to FIG. 8, the vibratorarrangement always moves during the production of a segment over theentire height (or depth) of the segment, i.e. the vibrator arrangement,after discharging filler material, moves through the discharged fillermaterial again as far as the base of the segment in order to compactsaid filler material. However, the filler material discharged in thefinal repeating step is then no longer compacted, but rather thevibrator arrangement moves as far as the upper end of the next segment,wherein the cavity located therebelow is filled with filler material.However, said filler material is subsequently only still compacted inthe region of the segment then to be produced.

FIG. 9 illustrates an alternative to the method according to FIG. 8 withreference to the production of a segment, in the example of the segmentbetween the ground depths x3 and x4. In this method, as also in themethod according to FIG. 8, at the beginning of the production of thesegment the vibrator arrangement moves from the lower end of saidsegment (at the position x4) to the upper end of said segment (at theposition x3), wherein the resulting cavity between x4 and x3 is filledwith filler material. The stroke or the upward displacement distance bywhich the vibrator arrangement is moved in this case is denoted by h1 inFIG. 9. However, the vibrator arrangement subsequently no longer movesdownward as far as the lower end of the segment, but rather, startingfrom the upper end, only by a distance or downward displacement distanceh2, where h2<h1, and subsequently upward again as far as the upper end,i.e. by the distance h2, such that the stroke h2 in the first repeatingstep is smaller than the stroke h1 in the first step. A stroke h3 in thenext repeating step is again smaller than in the preceding step. In theexample, after said repeating step, the production of said segment endsand the production of a new segment begins by the vibrator arrangementmoving (or being moved) as far as the upper end of the subsequentsegment.

The first stroke h1 defines the height of the segment. Said stroke is,for example, 1 m and is generally between 1 m and 2 m. In one example,provision is made for a difference Δh of the stroke (stroke difference)between two steps to be the same in each case. With regard to theexample according to FIG. 9, then: h1=h2+Δh and h2=h3+Δh. In oneexample, provision is made to raise the vibrator arrangement (and, inthe process, to discharge filler material) and again to lower saidvibrator arrangement with a reduced stroke (in order to compact thefiller material) until the stroke is smaller than or equal to apredetermined value. Said value corresponds, for example, to thedifference Δh. If, for example, h1=1 m and Δh=20 cm, the following stepsare carried out for the production of a segment: raising 1 m, lowering80 cm, raising 80 cm, lowering 60 cm, raising 60 cm, lowering 40 cm,raising 40 cm, lowering 20 cm, raising as far as the upper end of thenext segment. Via the stroke difference Δh, the number of repetitionsteps and therefore the diameter or the strength of the segment can beset in this method. In general, the diameter increases as the strokedifference Δh becomes smaller, since, in this case, more repeating stepsare carried out, and therefore more material is introduced.

In one method, provision is made for the column profile for each segmentto define the height thereof and the stroke difference Δh. In a furthermethod, provision is made for the column profile for each segment todefine the height thereof and the stroke difference Δh and, in addition,to define a maximum power consumption of the vibrator motor, wherein theproduction of a segment ends when the stroke is smaller than thepredetermined minimum value, i.e. when all of the repetition steps havebeen carried out, or when the maximum power consumption is reached. Inthe case of the previously explained vibrator arrangements which have asilo pipe or material pipe 11, filler material is introduced into theground from the silo pipe or material pipe. The dimensions, i.e. inparticular the diameter of the column, are produced by calculation fromthe integral of the quantity of filler material which is output into theground during the sum total of all the upward movements and which caneasily be calculated by the known cross section of vibrator and materialpipe and by the upward displacement distance. If, for example, thevibrator cross section is a cross section of 0.2 m², then at a point atwhich the vibrator moves up and down, for example, 5 times, a columncross section with an area of 5×0.2=1.0 m² is produced there bycalculation.

In a further exemplary embodiment of a vibrator arrangement (notillustrated), the pipe 11 is designed merely as an extension pipe. Inthis vibrator arrangement, filler material is introduced into the cavitybelow the vibrator arrangement by the fact that material is broughtdownward from above past the pipe, i.e. in an annular gap between thepipe 11 and the surrounding ground.

The previously explained method can be carried out fully automaticallyin a manner controlled by a computer. The computer is designed tocontrol the carrying device 2 and obtains information regarding theposition of the vibrator arrangement 1 by means of a suitable sensor andthe operating parameter (such as, for example, power consumption of thevibrator motor, insertion speed or vibration amplitude) of the vibratorarrangement. The controlling of the carrying device 2 by the computercan include, during the insertion, depending on the specific method, theinsertion of the vibrator arrangement 1 at a constant speed or aconstant application of force, wherein, during the insertion, thecomputer assigns the values obtained for the operating parameter to therespective ground depths in order thereby to obtain the ground profile.

The column profile can be produced automatically, i.e., for example, ina software-controlled manner, from the ground profile, as illustrated,for example, in FIG. 6. As explained, different segments which each havea predetermined height and property are defined in the column profile.Examples of such column profiles are illustrated in FIGS. 6 and 7. Theindividual segments can be produced corresponding to one of the methodsexplained previously with reference to FIGS. 6 to 9.

The controlling of the carrying device 2 by the computer for theproduction of each segment includes raising the vibrator arrangement atleast once by a predetermined displacement distance (upward displacementdistance) and lowering the latter again at least once by a predetermineddisplacement distance (downward displacement distance). As explained,upward displacement distance and downward displacement distance can beidentical in a step, but can also differ by a stroke difference Δh. Bothwhen a top vibrator is used with a silo pipe and when a depth vibratoris used with a silo pipe, during each raising of the vibratorarrangement filler material automatically flows into the cavity belowthe vibrator arrangement 1, and therefore it merely has to be ensuredthat there is always sufficient filler material in the silo pipe. Theheight of a segment to be produced, i.e. the displacement distance bywhich the vibrator arrangement 1 is raised for the first time from thebottom of the recess or from the upper end of a previously producedsegment, and the diameter and/or the strength of the material columnsection are controlled in a manner already explained by the computerdepending on the previously determined column profile which is dependenton the ground profile. The diameter and/or the strength of a segment iscan be set in the manner explained by the number of repetitions. In thecase of this automatic method, an equipment operator only still has achecking and safety function and moves the vibrator arrangement 1 withthe carrying apparatus 2 from point to point at which a material columnis intended to be produced.

The method can also be carried out as a semi-automatic method, in whichthe vibrator arrangement 1 is first of all inserted into the ground in acomputer-controlled manner and the ground profile is determined, and inwhich, during production of the material column 30, the carrying device2 is controlled by an equipment operator, to be precise depending onspecifications which are displayed by the computer on a display device(display). The display here shows symbols which, for example, indicateto the equipment operator in which direction the carrying device isintended to be moved, i.e. upward or downward, and how far the carryingdevice is intended still to be moved. A sequence (a-f) of such symbolsin the production of a material column section is illustrated in FIG. 8.In the example, a display for the symbols comprises a directional arrowas a first symbol and a displaceable bar as a second symbol. FIG. 8illustrates the display for seven different times. The directional arrowindicates to the equipment operator in which direction the carrying armis intended to be moved. An arrow upward, such as, for example, in FIGS.8 a and 8 b, symbolizes a movement upward, whereas an arrow downward, asin FIGS. 8 d, 8 e and 8 f, symbolizes a movement downward. The bar(illustrated shaded) indicates how far the carrying device 2 togetherwith the vibrator arrangement 1 is still intended to be moved in thedirection predetermined by the directional arrow. If the display iscompletely filled by the bar, as illustrated, for example, in FIG. 8 c,or is completely empty, as illustrated, for example, in FIG. 8 c, thereversing point for a reversal of the direction of movement of thecarrying device is reached.

The display is controlled by the computer depending on the previouslydetermined column profile and on the current penetration depth of thevibrator arrangement 1 or of the vibrator tip 13 in the ground. Themovement of the bar symbolizes here the movement of the vibratorarrangement 1 upward or downward. In the display according to FIG. 8, alower end of the display or of the bar marks a lower reversing point fora downward movement of the vibrator arrangement and an upper end marksan upper reversing point for an upward movement of the vibratorarrangement. Each of said reversing points represents a ground depth,wherein the ground depths represented by the upper and lower reversingpoint change over the course of the production of a pillar.

Depending on the type of production method, the upper and the lowerreversing point during the production of a segment can in each caseremain the same, or the upper reversing point can remain the same andthe lower reversing point can change. This is explained below for theproduction of a column segment which, in the case of the column 30according to FIG. 6, forms the lower column section 34.

In the case of a method according to FIG. 8, in which the vibratorarrangement is always moved over the entire height of the segment duringthe individual repeating steps, the lower reversing point of the displayalways represents the ground depth x4 and the upper reversing pointalways represents the ground depth x3. After production of the lowermostcolumn section or segment 34, the ground depth assigned to the upperreversing point changes, i.e. the display indicates a necessary upwardmovement of the vibrator arrangement 1 until the vibrator arrangementhas moved to a ground depth between x2 and x3, at which a first segmentof the column section 33 is produced.

In the case of a method according to FIG. 9, in which the stroke changeswith each repetition step, the upper reversing point always representsthe ground depth x3, and the lower reversing point changes with eachrepetition step, and therefore, for example, the first reversing pointduring a first insertion represents the ground depth x4−Δh, at a secondinsertion represents the ground depth x4−2Δh, and at a third insertion(not illustrated in FIG. 9) represents x4−3Δh, etc. After the lowermostcolumn section or segment 34 is produced, the ground depth assigned tothe upper reversing point changes, i.e. the display indicates anecessary upward movement of the vibrator arrangement 1 until thevibrator arrangement has moved to a ground depth between x2 and x3, atwhich a first segment of the column section 33 is produced.

The equipment operator does not have to know the actual position of thereversing points in the ground, the ground depth which is assigned to areversing point, and also the number of repetition steps per segment.These are predetermined by a computer or a control system on the basisof the previously determined column profile and are assigned to thereversing points of the display.

The display shows a first reversing point and a second reversing pointwhich are each assigned a ground depth, and a movement of the vibratorarrangement between the two reversing points both with respect to amovement speed and with respect to a direction of movement. For thispurpose, the position of the vibrator arrangement in the ground (betweenthe two reversing points) is detected at regular or irregular timeintervals and depicted on the display. In the example according to FIG.10, a lower reversing point is represented by a lower end of a displayand an upper reversing point is represented by an upper end of thedisplay, an arrow shows the desired direction of movement (predetermineddirection of movement) and a bar illustrates the position of thevibrator arrangement between the reversing points. Apart from a bar andan arrow, any other symbols for displaying the desired direction ofmovement and the extent of the movement still required are, of course,suitable.

The previously explained automatic or semi-automatic methods, in which amaterial column 30 is produced in the ground with a plurality ofsegments depending on a column profile, is independent of the manner ofdetermination of the column profile. As explained, said column profilecan be produced automatically from a ground profile which is determinedwhen the vibrator arrangement is inserted into the ground.

However, the column profile can also be produced manually from a groundprofile, such as, for example, from a ground profile determined when thevibrator arrangement is inserted into the ground, or else from a groundprofile determined by means of a core bore. For example, first of allonly the number and the position of the individual segments in thecolumn profile can therefore be predetermined, wherein the individualsegments are then manually assigned properties, such as, for example,diameter or strength (which determine the method for producing theindividual segments). Said assignment can take place depending on theground profile. This procedure can be selected in particular when theground construction is basically known, i.e. when it is known whichtypes of ground layers are present and in which sequence said groundlayers are present, but if it is not precisely known how thick theindividual ground layers are. In this case, the ground profile indicatesin particular the layer boundaries, i.e. indicates at which depths theboundaries between individual layers are located. An operator, such as,for example, a ground engineer, with knowledge of the position of thelayer boundaries, can then assign certain properties to individualsegments in the column profile. The column profile is displayed, forexample, on a display. Properties can be assigned to individual segmentsby means of any input tools, such as a keyboard, in a voice-controlledmanner or directly at the display, if the latter is designed as atouchpad, such as, for example, as a touchpad of a smartphone or of atablet computer. A column profile provided in such a manner can then beused in one of the previously explained production methods.

Features which have been explained previously in conjunction with anexemplary embodiment can, of course, also be combined with features ofother exemplary embodiments, even if this has not been explicitlymentioned previously, if said features do not cancel one another out.

1. A method, comprising: providing a vibrator arrangement which is heldon a carrying device which is designed to penetrate ground and which hasa vibrator motor; inserting the vibrator arrangement into the ground toa predetermined depth; and determining a ground profile of the groundwhen the vibrator arrangement is inserted, wherein the determination ofthe ground profile comprises measuring at least one operating parameterof the vibrator arrangement when the vibrator arrangement is insertedinto the ground, and wherein the ground profile in each case comprises aground parameter for at least two different ground depths.
 2. The methodas claimed in claim 1, further comprising: producing a material columnin the ground depending on the ground profile, using the vibratorarrangement.
 3. The method as claimed in claim 1, further comprising:inserting the vibrator arrangement, driven by the carrying device at atleast an approximately constant speed, into the ground; and measuring apower consumption of the vibrator motor as an operating parameter whenthe vibrator arrangement is inserted into the ground.
 4. The method asclaimed in claim 1, further comprising: exerting an at leastapproximately constant force on the vibrator arrangement by the carryingdevice when the vibrator arrangement is introduced into the ground; andmeasuring a speed at which the vibrator arrangement is inserted into theground, as an operating parameter.
 5. The method as claimed in claim 1,further comprising: inserting the vibrator arrangement, driven by thecarrying device at at least an approximately constant speed, into theground; and measuring a vibration amplitude of a tip of the vibratorarrangement as an operating parameter when the vibrator arrangement isinserted into the ground.
 6. The method as claimed in claim 1, whereinthe material column is produced depending on the ground profile in sucha manner that a diameter of the material column at a certain grounddepth is dependent on the ground parameter determined for said grounddepth.
 7. The method as claimed in claim 6, wherein the ground parameterdetermined for a certain ground depth is dependent on a ground densityand/or a ground rigidity, and wherein the material column is produced insuch a manner that the diameter of the material column increases withdecreasing ground density and/or decreasing ground rigidity.
 8. Themethod as claimed in claim 1, wherein the production of the materialcolumn comprises producing at least two segments, and wherein theproduction of each segment comprises: a) raising the vibratorarrangement by a predetermined upward displacement distance such that acavity arises below the vibrator arrangement; b) introducing a fillermaterial into the cavity; c) inserting the vibrator arrangement into thefiller material by a predetermined downward displacement distance; andd) repeating method steps a) to c) n times, where n≧0.
 9. The method asclaimed in claim 8, wherein the upward displacement distance and thedownward displacement distance in steps a) and b) are identical in eachcase.
 10. The method as claimed in claim 8, wherein the downwarddisplacement distance in step b) is smaller by a displacement difference(Δh) than the upward displacement distance in the immediately precedingstep a), and wherein, in each repetition, the upward displacementdistance in step a) is identical to the downward displacement distancein the immediately preceding step b).
 11. The method as claimed in claim10, wherein the displacement difference (Δh) in all of the repetitionsis identical.
 12. The method as claimed in claim 8, wherein, for theproduction of a material column section at a predetermined ground depth,the number n of repetitions in step d) is dependent on the groundparameter determined for said ground depth.
 13. The method as claimed inclaim 12, wherein the ground parameter is dependent on a ground densityand/or a ground rigidity, and wherein the number n of repetitionsincreases with decreasing ground density and/or decreasing groundrigidity.
 14. The method as claimed in claim 8, wherein a strength ofthe segment is measured during production, and in which the number n ofrepetitions is dependent on the measured strength.
 15. The method asclaimed in claim 1, wherein the vibrator arrangement comprises: avibrator pipe with an upper and a lower end; and a vibrator which isarranged on the vibrator pipe and has the vibrator motor.
 16. The methodas claimed in claim 15, wherein the vibrator is designed as a depthvibrator and is fastened to a lower end of the vibrator pipe.
 17. Themethod as claimed in claim 15, wherein the vibrator is designed as a topvibrator and is fastened to an upper end of the vibrator pipe.
 18. Themethod as claimed in claim 15, wherein the pipe is designed as a silopipe.
 19. The method as claimed in claim 1, wherein the carrying devicecomprises a carrying arm of earth-moving equipment.
 20. The method asclaimed in claim 1, wherein the carrying device comprises a mast and aslide movable on the mast.
 21. A method for producing a material columnin the ground, comprising: providing a vibrator arrangement which isheld on a carrying device and is designed to penetrate the ground;inserting the vibrator arrangement into the ground; repeatedly movingthe vibrator arrangement in the ground between reversing points, namelyan upper reversing point and a lower reversing point, and introducingfiller material into the ground when the vibrator arrangement is movedfrom the lower reversing point to the upper reversing point; anddetecting a position of the vibrator arrangement in the ground; whereinthe reversing points are predetermined by a control system, and whereina movement of the vibrator arrangement between the reversing points isdepicted in an electronic display which indicates a predetermineddirection of movement of the vibrator arrangement and the position ofthe vibrator arrangement between the reversing points.
 22. The method asclaimed in claim 21, further comprising: producing at least two segmentsof the material column, wherein the production of a segment comprises:a) raising the vibrator arrangement by a predetermined upwarddisplacement distance as far as an upper reversing point such that acavity arises below the vibrator arrangement; b) introducing a fillermaterial into the cavity; c) inserting the vibrator arrangement into thefiller material by a predetermined downward displacement distance as faras a lower reversing point; and d) repeating method steps a) to c) ntimes, where n≧0.
 23. The method as claimed in claim 22, wherein theupper reversing points in each repetition are identical, and in whichthe lower reversing points in each repetition are identical.
 24. Themethod as claimed in claim 22, wherein the downward displacementdistance in step b) is smaller by a displacement difference (Δh) thanthe upward displacement distance in the immediately preceding step a),and wherein each repetition the upward displacement distance in step a)is identical to the downward displacement distance in the immediatelypreceding step b).
 25. The method as claimed in claim 24, wherein thedisplacement difference (Δh) in all of the repetitions is identical. 26.The method as claimed in claim 21, wherein the display has a lower endwhich represents a lower reversing point and has an upper end whichrepresents an upper reversing point, and wherein a bar arranged betweenthe upper and the lower end indicates the position of the vibratorarrangement between the reversing points.
 27. The method as claimed inclaim 26, wherein a direction arrow in or next to the display indicatesthe desired direction of movement of the vibrator arrangement.